Uso de carboidrases em dietas à base de milho e farelo de soja para frangos de corte
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Data
2019-05-03
Autores
Pasquali, Guilherme Aguiar Mateus [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O uso de enzimas que degradam polissacarídeos não-amiláceos (PNAs) em dietas para monogástricos tem sido cada vez mais explorado por nutricionistas, apesar dos mecanismos pelos quais estas enzimas melhoram o valor nutritivo dos alimentos ainda não estarem totalmente esclarecidos. Assim, este estudo foi desenvolvido com o objetivo de evidenciar os principais mecanismos de ação de enzimas que degradam PNAs e o efeito sobre frangos de corte alimentados com dietas à base de milho e farelo de soja. O primeiro experimento, relatado no Capítulo II, foi desenvolvido para avaliar os efeitos da inclusão de diferentes produtos enzimáticos compostos por xilanase e β-glucanase em dietas à base de milho com dois níveis de energia para frangos de corte sobre o desempenho, características intestinais, umidade de cama, incidência de lesões de pododermatite, e parâmetros bioquímicos do sangue. Foram utilizados 1.200 pintos machos, distribuídos em esquema fatorial 2 × 4 (dois níveis de energia × ausência ou inclusão de três diferentes xilanases + β-glucanases). O ganho de peso e a conversão alimentar foram prejudicados pelo fornecimento de dietas de baixa energia (CN; 2.925 kcal/kg na fase inicial e 3.025 kcal/kg na fase de crescimento). O uso de diferentes produtos enzimáticos compostos por xilanase e β-glucanase não afeta o desempenho e a qualidade intestinal de frangos de corte alimentados com dietas à base de milho. O experimento referente ao Capítulo III teve como objetivo avaliar o efeito da inclusão de um produto enzimático composto por xilanase e β-glucanase em dietas à base de milho e soja com níveis variáveis de energia para frangos de corte, sobre desempenho, concentração de ácidos graxos de cadeia curta, pH e perfil térmico dos cecos, digestibilidade ileal de energia e proteína e cinética intestinal. Foram utilizados 744 pintos machos, alojados em 24 boxes e distribuídos em delineamento inteiramente casualizado em esquema 2 × 2 – dois níveis de energia × ausência ou inclusão de 100 gramas do produto enzimático por tonelada de ração. A suplementação enzimática melhorou o ganho de peso de 1 a 7, e de 1 a 21 dias, porém não afetou o desempenho de 1 a 35 dias. Frangos alimentados com dieta de baixa energia apresentaram maior concentração cecal de ácido acético quando suplementados com enzima. O fornecimento de dietas de baixa energia reduziu o pH do conteúdo cecal e aumentou a temperatura média dos cecos. A digestibilidade ileal de energia foi maior em frangos alimentados com dietas contendo xilanase, e de proteína e energia maiores com o fornecimento de dietas de alta energia. A inclusão do produto enzimático aumentou o tempo médio de retenção (TMR) no íleo distal, e o fornecimento de dietas de baixa energia reduziu o TMR no jejuno distal. Assim, a inclusão de xilanase em dietas à base de milho favorece o ganho de peso de frangos de corte apenas nas três primeiras semanas de vida, porém aumenta o tempo médio de retenção no íleo distal e melhora a digestibilidade ileal de energia.
The use of NSP-degrading enzymes in diets for monogastrics has been increasingly explored by animal nutritionists, although the mechanisms through these enzymes improve the nutritional value of the raw materials are still not clear. Thus, this study was carried in order to explore the mechanisms involved in the effects of NSP-degrading enzymes on broilers fed diets corn-soybean based diets. The first trial, reported in Chapter II, was carried out to evaluate the effects of different enzyme products composed by xylanase and β-glucanase in corn-based diets with two levels of energy on performance, intestinal parameters, litter moisture, incidence of pododermatitis, and blood parameters of broilers. A total of 1200 male chicks were distributed in a 2 × 4 factorial arrangement (two energy levels × absence or inclusion of three different xylanases + β-glucanases). Weight gain and feed conversion ratio were impaired when low energy diets were fed. In summary, the inclusion of different enzyme products composed by xylanase and β-glucanase does not affect the performance and intestinal quality of broilers fed corn-based diets. The objective of the second trial was to evaluate the effect of an enzyme product composed by xylanase and β-glucanase in varying energy corn-based diets for broiler chickens on performance, short chain fatty acid concentration on ceca, pH and thermal profile of cecum, energy and protein ileal digestibility and intestinal kinetics. A total of 744 male chicks were alloted in 24 floor pens in a completely randomized design in a 2 × 2 factorial arrangement - two energy levels × absence or inclusion of 100 ppm of the enzyme product. Enzyme supplementation improved weight gain from 1 to 7 and from 1 to 21 days, but did not affect performance from 1 to 35 days. Broilers fed the low energy diet showed higher cecal concentration of acetic acid when supplemented with enzyme. Broilers fed low energy diets presented reduced cecal pH and increased temperature of ceca. The ileal digestibility of energy was higher in broilers fed on enzyme supplemented diets, and ileal digestibility of protein and energy was higher when high energy diets were fed. Inclusion of enzyme increased the mean retention time (MRT) in the distal ileum, and broilers fed low energy diets presented reduced MRT in the distal jejunum. Therefore, although the inclusion of NSP-degrading enzymes in corn-based diets improves the weight gain of broilers only in the first three weeks, it increases the mean retention time in the distal ileum and improves the energy ileal digestibility
The use of NSP-degrading enzymes in diets for monogastrics has been increasingly explored by animal nutritionists, although the mechanisms through these enzymes improve the nutritional value of the raw materials are still not clear. Thus, this study was carried in order to explore the mechanisms involved in the effects of NSP-degrading enzymes on broilers fed diets corn-soybean based diets. The first trial, reported in Chapter II, was carried out to evaluate the effects of different enzyme products composed by xylanase and β-glucanase in corn-based diets with two levels of energy on performance, intestinal parameters, litter moisture, incidence of pododermatitis, and blood parameters of broilers. A total of 1200 male chicks were distributed in a 2 × 4 factorial arrangement (two energy levels × absence or inclusion of three different xylanases + β-glucanases). Weight gain and feed conversion ratio were impaired when low energy diets were fed. In summary, the inclusion of different enzyme products composed by xylanase and β-glucanase does not affect the performance and intestinal quality of broilers fed corn-based diets. The objective of the second trial was to evaluate the effect of an enzyme product composed by xylanase and β-glucanase in varying energy corn-based diets for broiler chickens on performance, short chain fatty acid concentration on ceca, pH and thermal profile of cecum, energy and protein ileal digestibility and intestinal kinetics. A total of 744 male chicks were alloted in 24 floor pens in a completely randomized design in a 2 × 2 factorial arrangement - two energy levels × absence or inclusion of 100 ppm of the enzyme product. Enzyme supplementation improved weight gain from 1 to 7 and from 1 to 21 days, but did not affect performance from 1 to 35 days. Broilers fed the low energy diet showed higher cecal concentration of acetic acid when supplemented with enzyme. Broilers fed low energy diets presented reduced cecal pH and increased temperature of ceca. The ileal digestibility of energy was higher in broilers fed on enzyme supplemented diets, and ileal digestibility of protein and energy was higher when high energy diets were fed. Inclusion of enzyme increased the mean retention time (MRT) in the distal ileum, and broilers fed low energy diets presented reduced MRT in the distal jejunum. Therefore, although the inclusion of NSP-degrading enzymes in corn-based diets improves the weight gain of broilers only in the first three weeks, it increases the mean retention time in the distal ileum and improves the energy ileal digestibility
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Palavras-chave
enzimas que degradam PNAs, xilanase, glucanase